Warm air furnace



WARM AIR FURNACE Filed April 18; 193B 3 Shuts-Sheet 1 INVENTOR )70I'Z'ZZX. Mueller:

Mareh 12, 1940. M. 1.. MUELLER WARM AIR FURNACE.

Filed April 18, 1938 3 Sheets-Sheet 2 INVENTOR 275/72 2 g. Mueller;

ATTORNEY March 12, 1940. M. 1.. MUELLER WARM AIR FURNACE Filed April 18,1938 3 Sheets-Sheet 3 INVENTOI? 772021281:

" Mil/[.92

lh arz'iz 4. BY

Patented Mar. 12, 1940 PATENT OFFICE WARM AIR FURNACE Moritz L. Mueller,Grosse Pointe, Mlch., asslgnor to Borg-Warner Corporation, Chicago,11]., a

corporation of Illinois Application April 18, 1938, Serial No. 202,670

5 Claims.

This invention relates to warm air domestic furnaces and moreparticularly to domestic furnaces which use oil for fuel and have fansor blowers for circulating air through the house.

ll One object of the invention is to provide a furnace in one unit whichwill be readily convertible between two ranges of heat output. With thisobject in view my furnace can be operated efficiently in different sizedhouses or in the same 10 house during different seasons without changingthe structure of the furnace.

Another object of the invention is to superimpose an automatic heatcontrolling feature upon the manual regulation mentioned above.

15 In this manner my furnace is adapted to be manually adjusted for lowor high heat output and to be further automatically controlled for aminimum or maximum output within each operating range.

20 Another object of the invention is to provide a furnace unit whichmay be readily adapted to form a house cooling or ventilating unit inthe summer time.

Another object of the invention is to provide 25 a furnace unit whichwill filter the air each time it is circulated through the house.

Other objects of my invention will be apparent from a consideration ofthe following specification and drawings of which there are three (3) 30sheets and in which:

Fig. 1 represents a broken away isometric view of the furnace;

Fig. 2 represents a section taken along the line 2-2 of Fig. 1 andlooking in the direction of the 35 arrows;

Fig. 3 represents a vertical section through one of the stoves and oilburners shown in Figs. 1 and 2;

Fig. 4 represents the control handle and panel 40 for selecting theheating or cooling position of the damper which controls the fiow of airthrough the furnace;

Fig. 5 is a vertical section through the valve shown in Fig. 1 and takenalong the line 55 as looking in the direction of the arrows;

Fig. 6 is a vertical section through the relief damper and balanceweight shown in Fig. 2;

Fig. 7 is a vertical section taken along the line 1-1 of Fig. 1; and

so Fig. 8 is a circuit diagram of the electrical connections foroperating the unit.

The furnace unit is contained within a shell or casing generallyindicated at l which is made up of metal sheets or plates bolted orwelded to- 55 gether in any suitable fashion. The casing is divided intoseveral compartments as indicated in Fig. 2 where A represents the coldair intake compartment, B represents the blower compartment, Crepresents the heating compartment, D represents the draft chamber, Erepresents. the cooling compartment and F represents the filtercompartment. A door l5 in the front panel provides access to the heatingcompartment C. A door I! with a handle 19 on each side of the casing Illprovides access to the space between a filter I8 10 and a cooling coil50 and provides for their service or removal therethrough.

Air'is drawn from the intake compartment A through the filtercompartment F by the blower B and is delivered into the heatingcompartment C from where it is forced out into the heating system of thehouse.

The intake compartment comprises the back portion of the furnace and Iprovide for various panels of. the casing to be removed to form intakepassages. The top panel Il may be removed if it is convenient to havethe air intake supplied to the top of the furnace. As an alternativesupply passage, either part or all of the back panel I! may be removedor the air intake duct may be connected to the bottom of the furnace atthe opening indicated at l3.

The intake compartment is further formed by the vertical portion ofpanel I4, the relief damper l6 and the filter I8.

The filter l8 may be of any desired construction which will remove dustand impurities from the air as required by the individual users. Iprovide for it to be supported upon a cross piece or angle iron 20 andsecured at the top by an angle iron 22 and a depending flange 24, a partof. the outer casing.

The relief damper I6 extends completely across the furnace and is moreclearly indicated in Fig.

6 and its construction and operation is as follows: The damper comprisesa sheet of metal 30 bent or shaped around a horizontal center member 32and fastened thereto by bolts 33. The center member 32 has holes in eachend through which is run the shaft 34. The shaft 34 extends through andis carried by the side panels of the furnace. The damper I6 is preventedfrom rotating on shaft 34 by keys 35. It will be noted that the damperis unbalanced in that the upper side 36 is longer than the lower side38.

Directly in back of the shaft 34 I provide a clip or lug 40 which may bebolted through the damper to the center member 32 or may be weldeddirectly to the damper. To the clip 40 I fasten the shaft 54 by a key68.

a hollow cylinder 42 by means of a strap iron 44 and bolts 45. Withinthis cylinder 42 I place a heavy metal ball 46. .The cylinder 42 isinclined downward toward the rear in such a manner that the ball 46 willnormally be at the rear end of the cylinder.

From the above construction it is apparent that if the damper is rotatedin a counterclockwise direction the-ball 46 will roll forward in thecylinder 42 and so unbalance the damper that it will not return to itsvertical position without the application of outside force. I providehandles on each end of the shaft 34, outside the furnace, which indicatethe position of the damper and by which the damper may be set. Since theupper arm of the damper is larger in area than the lower arm, the forceof air due to the suction of the blower exerted against the upper armwill be greater than that against the lower arm. If the filter I8 isclean it will offer little resistance to the air drawn through it by theblower and the weight of the ball 46 at the rear end of the cylinder 42will be sufiicient to counterbalance the uneven force of the air on thedamper I6, however, if the filter becomes clogged there will be anincreased pressure on the damper until it is unbalanced and is rotatedcounterclockwise in which case the ball 46 will roll as explained beforeand will keep the damper in its new position. The weight of the ball 46at the forward or lower end of cylinder 42 will keep the cylinder in anupright or vertical position and will maintain the damper in ahorizontal or open position thus allowing air to be by-passed around thefilter I8.

After the air has entered the filter chamber F it may pass directly tothe blower chamber B or may be directed through the cooling coil 50according to the position of the control damper The control damper 52extends completely across the furnace and is composed of a metal platepressed or fastened around a shaft 54 and fastened to said shaft by pinsor keys 56. The shaft 54 extends through and is journaled in the uprightangle irons 58 on each side of the furnace.

The outside ends of the shaft 54 extend through an indicator plate 62which is shown in Fig. 4. This plate is bolted to the casing through theholes 64. A handle 66 is keyed to each end of The handle 66 carries apointer 61 and a bolt or set screw I0 which may be screwed in to engageholes 12 in the indicator plate 62 to lock the handle and the controldamper in either the heating or cooling position.

The cooling coil 50 may be either a. brine coil or evaporator coil ofany suitable refrigerating system. It may be supported at its top sideby such means as angle irons I6 and at the bottom on a cross member 60which is supported on the upright angle irons 58 just above the damper52.

When the control damper 52 is in a vertical position it will be closelyspaced from the cross member 60 and will nearly touch the horizontalportion of plate I4 at the bottom. Since it extends from side to side inthe furnace the only passage open for the fiow of air is through thecooling coil 50 and the cooling compartment E. When the damper is raisedto a horizontal position it remains in contact with the cross member 60and the sides of the furnace and its lower end abuts against thePartition plate I00 thus closing off the cooling compartment E andallowing air to flow directly from the filter compartment F to theblower compartment B through the opening vacated by rotating the damper.

The blower for the furnace may be of any desired construction withsufllcient capacity. In my embodiment of the invention I have provided afan on a shaft 62 within a metal shell or hood 84. The shaft 82 isjournaled at each end in bearings 86 which are supported on framework88. Air is drawn in through holes in each side of the hood.

The framework 88 is made up of angle irons and also forms a mount forthe electric motor 90 which drives the fan 80 through the belt 82 andpulleys 04. Power is supplied to the motor through cable 0|.

The heating compartment is separated from the cooling and blowercompartments by the metal plate I00 which extends completely across thefurnace from side to side. The blast from the blower is delivered intothe heating compartment through the opening I02.

The heating compartment contains two stoves H0 and H2 which support aradiator II4 by means of clips H6. Air from the blower is directedbetween the two stoves and is there split into two currents by thebafile H8. The air is thus blown in a spiral path around each stoveupward and around the radiator II4 from where it is exhausted throughthe opening I20 into the heating system of the house.

Each of the stoves is composed of a sheet metal cylinder open at thebottom and with a connection I23 at the top for a fiue I22. Each stovehas a circular opening closed by a door I24 through which the fire potmay be inspected and the fire lighted. A raised portion IIS of thebafile protects the operator from the direct blast of the blower when sodoing.

Near the lower end of each stove is an impressed ring I28 which supportsthe stove and forms a seal with the flange I4I of the fire pot I40. Thestoves are fastened down to the fire pots by means of rods I30 whichhave hooks slipped through slots I3I in the stoves and are then passedthrough holes in the supporting channels I52 and drawn down by nuts I33.

The draft chamber D is separated from the heating chamber C by a plateI42 and from the blower compartment by a plate I44. Air is admitted tothe draft chamber through a port or hole I46 in the plate I42. This holemay be covered wholly or in part by the damper I48 which is adjustableto regulate the amount of air to be admitted. Damper I48 is fastened toplate I42 by a pin I41 and may be moved in a plane just over hole I46 bymeans of handle I49.

The draft chamber contains a supporting framework composed of metal legsI50 and supporting channel irons I52. These supporting channel ironsform supports for the legs I ll of the fire pots I40 and the stoves III!and H2 as mentioned before. I also provide a plate I54 below each stovefor catching dust or oil from the burners.

The operation of the burners is as follows: Oil is suppiied to thebottom of the burners by pipes I60 and I62 from the valve I64. Airenters through the port I46 and is drawn in through the holes I56 whereit is burned with the oil and the burned gases are forced upward throughthe hole I58 in the top of the burner. From there the gases rise in thestoves and are forced out through the flue I22 into the radiator I I4.The radiator I I4 is formed of sheet metal and contains baffles II5around which the stack II1.

- the crank 222 by link 284. The cranks 222 are gases must pass beforepassing out through the The dotted arrows indicate the path of theproducts of combustion.

The draft chamber also contains an exhaust chamber and damper generallyindicated at I18. This chamber is indicated as Fig. '1 in which I12represents a rectangular metal sleeve open at one end I14 and extendingthrough a hole in the front wall of the casing I8 at I18. The hole I18may be covered by an ornamental grill such as I18. Near the rear end ofthe sleeve a rectangular frame formed of metal angles is formed 'asindicated at I88. This may be fastened inside the sleeve by welding orby means of screws I8I as shown. The frame I88 carries the shaft I82 inholes provided at the top of its side 'members. Aroundthe shaft I82 isformed a sheet metal damper I84 which is free to rotate with or to rockon the shaft I82.

When the damper I48 is properly adjusted a quantity of air will beforced into the draft chamber which is more than sufficient tocompletely burn all of the oil supplied to the burners. This air will beat a higher pressure than the atmosphere surrounding the furnace as itis desirable to maintain the pressure in the draft chamber at a'predetermined pressure to maintain a specific stack pressure or draft.To accomplish this result the damper I84 may be' weighted so that itwill swing forward under the pressure of the air in the draft chamber toa position that will allow the proper amount of air to escape throughthe grill I18. In this manner if the pressure in the draft chamber risestoo high the damper I84 will swing further forward and allow more air toescape. The damper acts as an automatic variable resistance building upthe pressure behind it in the draft chamber to a point determined by theangle of the damper.

Fig. 5 represents a section through the valve supplying oil to the twostoves and the controls for operating the valve. While the valve is notclaimed as part of my invention, it is described to explain the mannerin which my furnace operates.

The valve is composed of a metal case I88 with an intermediate dividingwall I82. It may be supplied with a removable cover plate I84 throughwhich access may be had to the mechanism of the valve.

I98 indicates a pipe by which oil is supplied to the valve. The oil isallowed to flow into the valve proper through a needle valve I81 whichis controlled by a float 288 in such a manner as to maintain apredetermined level of oil in the valve.

2I8 indicates a solenoid or relay supported at the center of the valveby cross members 2I2. This is arranged to be energized by current fromthe control mechanism, which will be described later, through the cable2 and contacts 2I8.

A fixed shaft 228 extends completely across the valve and carries towardeach side a crank member 222. The tops of these crank members 222 areconnected by an L-shaped cross piece 224 and are adapted to rotatearound the shaft 228. The cross piece 224 carries at its center a pieceof metal 228 which will be attracted to the solenoid 2I8 when thesolenoid is energized. This will operate to rotate the cranks 222 in acounterclockwise direction.

Projecting inwardly from the sides of the valve are two short shafts 228each of which carries another crank member 288. Each crank 288 has acentral pivot 232 which is connected to urged downward by springs 288which are fastened to the cranks 288 near the pivots 282 and to a ringformed on the valve casing at 288. When the solenoid is energized thecranks 222 will rotate in a counterclockwise direction and links 284will operate to rotate the cranks 288 also in a counterclockwisedirection. The free ends of the cranks 288 engage shoulders 248 on twoneedle valves 242 and the counterclockwise rotation of the cranks 288operates to raise each needle 242.

Eachneedle 242 has three shoulders 248, 244 and 245. The shoulder 245 isdesigned to close the opening 248 and the shoulder 244 is designed toclose the opening 248. Shoulder 248 is designed to engage the surfacethrough which opening 248 is formed and acts to limit the downwardmovement of the needle 242.

Each needle 242 operates in a series of chambers and passages asfollows: 258 is an annular space which is open to the supply chamber I88through port 252 and to a delivery chamber 254 through the port 248. 258is. another annular chamber which is open to the supply chamber I88through port 258 and to the connecting chamber 288 through the port 248.Connecting chamber 288 is open to the delivery chamber 254 through theport 282. The delivery chamber 254 of each of the above series isconnected by a pipe to one of the fire pots I48.

When the needle is in its completely raised position oil may flow fromthe chamber I88 through the port 252, chamber 258, port I48 into thedelivery chamber 254, and may also flow through the port 258, chamber258, port 248, chamber 288, port 282 into the delivery chamber 254. Ifthe needle is partially lowered the shoulder 244 will close the port 248shutting off the supply of oil through that port but will not close theport 248. Thus the supply of oil to each furnace may be regulatedbetween two amounts determined by the sizes of the ports 248 and 248.

The needle 242 is normally held in position by means of a spring 28Iwhich bears on the upper surface 284 of the needle 242 in such aposition as to close port 248 but not port 248.-

The needle setting may be adjusted by turning the thumbscrew 286. I Y

When the crank 288 is rotated in a counter clockwise direction throughthe action of the solenoid 2I8, as described before, the needle will beraised against the compression of spring 28I by the action of the crank288 against the shoulder 248. This operates to open both of the supplyports and delivers the larger amount of oil to the delivery chamber 254as explained before.

The plunger 218 passes through a friction connection-212 in the coverplate I84 and extends downward until it is in contact at its lower end214 with the crank 288. The plunger 218 is slidably fastened to thecrank 288 by a stirrup or ring 218. The plunger 218 also carries aprojection or shoulder 218 which is adapted to engage the top of theneedle 284 after the plunger has been depressed some distance.

When the plunger 218 is depressed it will first rotate the crank 288 ina clockwise direction until the fixed pivot 228 is on the right handside of the link 284. From this position any upward movement of the link284 will tend to give the crank 288 a clockwise rotation rather than acounterclockwise rotation and will not affect the position of the needle242.

After the crank :30 has been pushed to 1e e inoperative position,further depression of the.

plunger 2'! will engage the top of the needle 242 and will depress it toclose both ports 248 and 248. The friction connection 212 will hold theplunger 210 down until it is pulled upward by some outside force. whenit is pulled up the stirrup 216 will pull the crank 230 back to itsoriginal operative position.

From the above it is apparent that each of the cranks 222 may be given acounterclockwise rotation by action of the solenoid III with or withoutaffecting the position of the needles 242 according to the position ofthe cranks 230 as determined by the position of the plungers 2". In thismanner both needles may be left in control of the solenoid or either orboth may be taken out of its control and closed.

Considering now the operation of the furnace as a whole: If bothplungers 210 are left up the valve will supply a set minimum or maximumamount of oil to each furnace thus giving two ranges of heat output say100,000 or 20,000 B. t. u.

per hour. However, either one of the furnaces may be shut oiI completelyby depressing one of the plungers 210 and the valve will then functionto supply 011 to only one of the furnaces thus giving two smalleramounts of heat, 10,000 or 50,000 B. t. u.-per hour, according to theaction of the solenoid.

Fig. 8 indicates one way in whichthe furnace may be controlled. A 110volt electricity supply is provided on the line 299. Some current istaken from the line by the step-down transformer 292. A thermostat 294will be placed in the space or room to be heated. When the thermostat294 is closed, there will be a complete circuit through the thermostat294, transformer 292, and the valve I64. The valve then operates tocontrol the furnace as described above.

The motor 90, for operating the blower, may or may not be connected forregulation by the thermostat 294 and I have shown it to be manuallycontrolled by the switch 300.

It is to be understood that I intend this specification to bedescriptive only and not limiting on my invention.

I claim:

1. In a furnace of the type described, a casing defining an air heatingchamber, two stoves supported in said heating chamber, means to direct ablast of air transversely between said stoves, a baiile to split saidair blast into two spiral paths, and means shielded from said air blastby said baflle for supplying air for combustion in said stoves.

2. In a furnace of the type described, a casing defining an air heatingchamber, two upright cylindrical stoves supported in said heatingchamber, means to direct a blast of air transversely between saidstoves, and a baille extending halfway around .the front of each stove,said baiiles being joined in the center and operable to direct the airblast in two spiral paths upward and around each stove.

3. In a furnace having a casing defining a heating compartmentcontaining two cylindrical stoves and a radiator common to both stoves,means for directing a blast of air transversely between said stoves,means for causing said air to spiral upwardly around each stove andaround said radiator, means for joining the aforementioned currents ofair for delivering them to a house heating system.

4. In a furnace of the type described, a casing defining a heatingchamber, two upright cylindrical stoves supported in said chamber, arectangular radiator above said stoves, said radiator being connected toreceive the burning gases from said stoves, means for directing a blastof air transversely between said stoves, and means to divide said airblast into two spiral paths upward around each stove and said radiator.

5. In a furnace containing a heating compartment, two stoves within saidcompartment, a single door in said compartment wall giving access toboth stoves, means for directing a blast of air between said stoves, abalfle between said stoves for guiding the direct blast of air away fromsaid door and around each of said stoves.

MORITZ L. MUELLER.

